JPS6484448A - Optical information reading mechanism - Google Patents

Abstract

PURPOSE:To reduce the number of optical parts, and to lower cost by providing a concave mirror with an optical path folding function instead of an illuminating lens, and providing the concave mirror with the optical path folding function and an aberration correcting lens instead of an imaging lens. CONSTITUTION:In y-axis direction, light emitted from an LED 1 comes incident to an illuminating concave mirror 2, and all the light is converged upon a reading line center P. Reflected light from the center P is incident on an imaging concave mirror 4a, and its light is incident on the aberration correcting lenses 4b, 4c, and after aberration is corrected, is imaged on a CCD 5. Besides, in x-axis direction, the light emitted from the LED 1 is due to be converged at the vicinity of the aberration correcting lens 4b by the illuminating concave mirror 2, but before that, it comes incident on the correcting lens 4b after passing through the line center P. Since the light emitted from the center P has the aberration when it is imaged, distortion and image plane bulge are corrected by the aberration correcting lenses 4b, 4c, and it is imaged on the CCD 5 in a state that the aberration is comparatively small. Thus, since the functions of the illuminating lens and the optical path folding mirror are substituted by one concave mirror, the number of the parts can be reduced.